Optimal threshold of a control parameter for tomotherapy respiratory tracking: A phantom study.
J Appl Clin Med Phys
; 24(5): e13901, 2023 May.
Article
em En
| MEDLINE
| ID: mdl-36635847
ABSTRACT
BACKGROUND:
Radixact Synchrony® , a real-time motion tracking and compensating modality, is used for helical tomotherapy. Control parameters are used for the accurate application of irradiation. Radixact Synchrony® uses the potential difference, which is an index of the accuracy of the prediction model of target motion and is represented by a statistical prediction of the 3D distance error. Although there are several reports on Radixact Synchrony® , few have reported the appropriate settings of the potential difference threshold.PURPOSE:
This study aims to determine the optimal threshold of the potential difference of Radixact Synchrony® during respiratory tumor-motion-tracking irradiation.METHODS:
The relationship among the dosimetric accuracy, motion tracking accuracy, and control parameter was evaluated using a moving platform, a phantom with a basic respiratory model (the fourth power of a sinusoidal wave), and several irregular respiratory model waveforms. The dosimetric accuracy was evaluated by gamma analysis (3%, 1 mm, 10% dose threshold). The tracking accuracy was measured by the distance error of the difference between the tracked and driven positions of the phantom. The largest potential difference for 95% of treatment time was evaluated, and its correlation with the gamma-pass ratio and distance error was investigated. The optimal threshold of the potential difference was determined by receiver operating characteristic (ROC) analysis.RESULTS:
A linear correlation was identified between the potential difference and the gamma-pass ratio (R = -0.704). A linear correlation was also identified between the potential difference and distance error (R = 0.827). However, as the potential difference increased, it tended to underestimate the distance error. The ROC analysis revealed that the appropriate cutoff value of the potential difference was 3.05 mm.CONCLUSION:
The irradiation accuracy with motion tracking by Radixact Synchrony® could be predicted from the potential difference, and the threshold of the potential difference should be set to â¼3 mm.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Radioterapia de Intensidade Modulada
/
Neoplasias
Tipo de estudo:
Prognostic_studies
Limite:
Humans
Idioma:
En
Revista:
J Appl Clin Med Phys
Assunto da revista:
BIOFISICA
Ano de publicação:
2023
Tipo de documento:
Article
País de afiliação:
Japão